In recent years, as personal computers have widely spread over, digital cameras capable of easily inputting picked-up images in the digital cameras to the personal computers have gained popularity. Further, it becomes general that a digital camera is installed into an information processing apparatus, such as, a mobile computer, a cellular phone and a PDA (Personal Digital Assistance). As the digital camera gains popularity, a smaller digital camera is demanded. When the size of a camera becomes small, vibration accidentally transmits to the image pickup optical system of the camera and image-shake occurs. Accordingly, various zoom lenses having anti-shake mechanism for performing the shake compensation have been proposed. For example, Japanese Patent Applications Open to Public Inspection Nos. H7-92431 and 2001-100099 disclosed a zoom lens of four lens groups having positive power, negative power, positive power and positive power in the order from the object side. In the disclosed zoom lens, the fourth lens group with a positive power includes a plurality of lenses which are arranged to shift in the direction substantially perpendicular to the optical axis of the lenses, in order to conduct image compensation.
However, the zoom lens for shake compensation disclosed in Japanese Patent Applications Open to Public Inspection Nos. H7-92431 and 2001-100099, includes a lens group which is designed to shift in the direction substantially perpendicular to the optical axis of the lens for shake compensation and which is formed of a plurality of lenses. Accordingly, the mass of the lens group for shake compensation becomes large. As a result, the power consumption of the actuator for driving the lens group for shake compensation increases and the structure of anti-shake mechanism becomes complex, which results in that a zoom lens barrel becomes large.